DNA and Protein Synthesis

Question 1

Why is DNA universal?

Answer 1

The genetic code is the same in all living organisms

Question 2

What does GGT code for?

Answer 2

Glycine

Question 3

Why is DNA Non-Overlapping?

Answer 3

Each DNA triplet and gene is separate

Question 4

Why is DNA degenerate?

Answer 4

The same amino acid can be coded for by more than one triplet

Question 5

How does DNA become pre-mRNA?

Answer 5

It is transcribed

Question 6

How does pre-mRNA become mRNA?

Answer 6

It is spliced

Question 7

How does mRNA become proteins?

Answer 7

it is translated

Question 8

How is genetic information stored in eukaryotes?

Answer 8

• Long, linear double helix- Found in nucleus- Folded around histones- Folded into chromosomes - Containing introns and exons

Question 9

How is genetic information stored in prokaryotes?

Answer 9

• Short circular loop of DNA- No histones- No nucleus- Have plasmids- No introns

Question 10

What is a gene?

Answer 10

A sequence of DNA that codes for a polypeptide, protein or functional RNA

Question 11

What is the locus?

Answer 11

The position of a gene on a chromosome, the location of the specific gene will remain the same in all organisms of the same species

Question 12

What is a DNA triplet?

Answer 12

A sequence of 3 DNA bases that code for a specific amino acid

Question 13

What were mitochondria and chloroplasts initially?

Answer 13

Free living therefore they contain their own DNA, they can synthesise enzymes needed for their functions

Question 14

What are introns?

Answer 14

Non coding multiple repeats that are found in pre-mRNA and do not code for polypeptides

Question 15

How is transcription carried out? (before splicing)

Answer 15

• DNA helicase separates out DNA strands by breaking hydrogen bonds- Free RNA nucleotides attach to the template strand by complimentary base pairing- RNA polymerase joins RNA nucleotides together with phosphodiester bonds formed by condensation reactions- H-bonds reform- premRNA is formed in eukaryotes- mRNA is formed in prokaryotes

Question 16

What is splicing?

Answer 16

Removal of introns (non coding sections)

Question 17

Which organisms do not undergo splicing

Answer 17

Prokaryotes

Question 18

How does splicing happen?

Answer 18

premRNA (introns and exons) undergoes splicing to remove the non coding sections (introns) to leave just the coding sections (exons) and mRNA is formed

Question 19

What happens after splicing?

Answer 19

mRNA leaves the nucleus and undergoes translation in the cytoplasm

Question 20

What is a codon?

Answer 20

A triplet of bases found on mRNA that codes for a specific amino acid

Question 21

What is an anticodon?

Answer 21

A triplet of bases found of tRNA that is complimentary to the mRNA codon

Question 22

What is tRNA?

Answer 22

Transfer RNA, a polypeptide folded by H-bonds with an amino acid attached. The amino acid is specific to the anticodon

Question 23

How does translation take place?

Answer 23

• A ribosome binds onto mRNA at the start of the start codon- Codon on the mRNA is matched to the complimentary anticodon on tRNA by complimentary base pairing - Ribosome hold the complimentary tRNA in place whilst the amino acids are joined together by a peptide bond- Used tRNA returns to the cytoplasm to attach to a new amino acid (complimentary to its anticodon) this uses ATP

Question 24

Where does the ribosome attach and detach?

Answer 24

The start and stop codons

Question 25

What is formed from translation?

Answer 25

A polypeptide chain

Question 26

After a mutation, what changes within the DNA?

Answer 26

The sequence of bases

Question 27

Within a bacterial cell, around which protein does the DNA wind?

Answer 27

Not wound as it is prokaryotic

Question 28

What do we call a sequence of three bases within a DNA strand?

Answer 28

Triplet

Question 29

What do we call a sequence of three bases on a mRNA strand?

Answer 29

Codon

Question 30

What do we call a sequence of three bases on a tRNA strand

Answer 30

Anticodon

Question 31

What can a pair of matching chromosomes be defined as?

Answer 31

Homogenous pair

Question 32

What type of cells are plant cells?

Answer 32

Eukaryotic

Question 33

What can the locus of a gene be defined as?

Answer 33

The position of a gene on a chromosome

Question 34

Within a plant which organelle stores genetic information?

Answer 34

Nucleus

Question 35

What is the different form of a gene known as?

Answer 35

An allele

Question 36

What is the base sequence of DNA having a change occur known as?

Answer 36

A mutation

Question 37

How could a non-functional enzyme come about?

Answer 37

High temperatures, change in pH or a mutation of the gene that coded for the protein

Question 38

Where, within a cell, are proteins produced?

Answer 38

Ribosomes

Question 39

A human sperm cell contains how many chromosomes?

Answer 39

23

Question 40

Within our body cells, we have a total of how many chromosomes?

Answer 40

46

Question 41

Where is human DNA stored?

Answer 41

Chromosomes

Question 42

One amino acid is coded for by how many bases?

Answer 42

3

Question 43

In which organelle does transcription happen?

Answer 43

Nucleus

Question 44

RNA is made of how many strands?

Answer 44

1

Question 45

Two amino acids are held together by which type of bond?

Answer 45

Peptide

Question 46

Which base is not in an RNA strand?

Answer 46

Thymine

Question 47

In which organelle does protein synthesis occur?

Answer 47

Ribosome

Question 48

DNA is transcribed into what type of RNA?

Answer 48

pre-mRNA / mRNA

Question 49

Amino acids are joined together by which type of reaction during protein synthesis?

Answer 49

Condensation

Question 50

Within protein synthesis, where does translation take place?

Answer 50

Ribosome

Question 51

What type of sugar forms part of an RNA molecule?

Answer 51

Ribose

Question 52

What does the DNA antisense strand act as?

Answer 52

The template strand for mRNA

Question 53

What is the DNA antisense strand complimentary to?

Answer 53

The DNA sense strand

Question 54

What does the DNA sense strand not act as?

Answer 54

The template strand for mRNA

Question 55

What does pre-mRNA contain that need to be removed?

Answer 55

Introns

Question 56

How are introns removed?

Answer 56

pre-mRNA is spliced to remove introns and leave the coding exons (eukaryotes only)